Middlebury College team invents hydrogen tractor
MIDDLEBURY — French inventor François Isaac de Rivaz created one of the first internal combustion engines at the beginning of the 19th century. It ran on hydrogen gas. Around that same time, a nascent Middlebury College hired its first mathematics professor, expanding its offerings into the sciences. Now, more than 200 years after the onset of these seemingly unrelated events, their historic ripples have collided.
Last week, a team of scientists and technicians, led by eight Middlebury physics students and two 1956 graduates, unveiled what they believe is the first hydrogen gas-powered internal combustion engine in a tractor. While the tractor runs smoothly, emitting clean water vapor, there are still several obstacles to overcome before it’s ready for practical use.
The vision is of a fossil fuel-free agricultural landscape, where hydrogen power is produced on each farm using electrolysis, a technique that uses an electric current to split water into hydrogen and oxygen atoms. Picture a pastoral Vermont farm with a windmill powering an electrolysis operation that creates hydrogen for a tractor.
“Generally, we think of hydrogen as used in fuel cells, where the chemical potential between hydrogen and oxygen is used to drive an electric motor,” said Alex Clement, a senior at Middlebury. “It’s pretty rare to have hydrogen actually run an internal combustion engine.”
In December, New Holland rolled out the world’s first hydrogen fuel cell-powered tractor. The prototype NH2 features a 106-horsepower engine. So why didn’t the Middlebury team build on new fuel-cell technology?
“The internal combustion engine is more versatile and it’s less expensive” than using fuel cells, said Mark Benz, a former General Electric inventor who ignited the local undertaking.
Converting a combustion engine to run on gas can be done inexpensively, the Lincoln resident said, and the engine can also run on other gases like methane, a biogas from cow manure. This methane option, said Benz, has piqued the interest of many local farmers.
THE TRACTOR’S STORY
Benz, a 1956 Middlebury College graduate with numerous patents to his name, became interested in hydrogen combustion engines in the 1990s when he was inspired by a man named Ben Jordan, who converted a Ford Model T engine to run on hydrogen. For years, Benz talked about replicating the idea for farm use until, one day, his former college roommate, Dick Catlin of Addison, said, “Let’s do it.”
In 2007, they acquired a 1948 Ford 8N tractor with a four-cylinder engine. The two friends told Middlebury College administrators about their idea to convert a tractor engine to run on hydrogen. The 78-year-old men didn’t want to be the ones driving the process; the way they saw it, young thinkers should grab the reins of their future. They wanted Middlebury physics students to call the shots. In 2008, four Middlebury students spent a semester doing just that.
The students outfitted the tractor with specialized fuel lines, fuel injectors and a digital control system. They also installed a computer on the tractor to control the injectors and the spark timing.
“At the end of the spring in 2008, they got it to sputter on hydrogen. It turned over for about 40 seconds on their very last day of class,” said Chester Curme, a physics major who graduated last weekend. “So we took it up four years later (as a winter-term class) and we made it actually run properly.”
In just a month, a team of eight Middlebury students, representing freshman through senior classes, had accomplished what they weren’t sure was even doable. With additional help from their professors and Champlain Valley Equipment — which volunteered space, time, equipment and employee guidance — the students successfully converted a 64-year-old gasoline engine to run on hydrogen.
First they converted it to run on propane. Then they figured out how to run it on compressed natural gas, which is a step closer to hydrogen on the molecular level. Finally, last Monday, they started the tractor with hydrogen, which the college obtained from a commercial supplier in Rutland. The tractor engine revved up to 16 horsepower out of a potential 22 horsepower.
“Are you ready to see it in action?” asked junior Harry Philip last week in the garage at Champlain Valley Equipment off Exchange Street in Middlebury. He turned the key, and the red tractor ignited to a smooth roll.
“It’s music to our ears every time we start it up,” he said.
Over the soft chugging of the tractor, Clement explained that the tractor runs better than the same Ford 8N model that Benz currently runs on gasoline at his home.
“In our specific instance, we’ve noticed that it runs dramatically more smoothly on hydrogen than on any other fuel we’ve run it on,” said Clement. “And it sounds smooth compared to other similar tractor models that run on gas.”
Hydrogen, which is more than twice as energy-dense as gasoline, doesn’t produce carbon dioxide when burned at low temperatures.
“All of the other gases we were working with are hydrocarbons. So when they burn, you get carbon dioxide or carbon monoxide,” said Clement. “When you burn hydrogen, especially at low enough temperatures, the only byproduct is water.”
“Theoretically our only exhaust is water,” chimed Curme. To demonstrate this phenomenon, Catlin put his face up to the exhaust pipe and breathed in the benign vapors.
Catlin, Benz and the Champlain Valley Equipment staff are impressed with the students’ results, but the tractor still hasn’t reached its full potential, and storage is an even bigger problem. Right now, the tractor can run at full speed for only five minutes, and that’s with a large tank of hydrogen. A Middlebury student who isn’t part of this project is searching for a solution to this issue. The students said she’s looking for a way to store hydrogen at a lower pressure and higher density to reduce the risk of explosions and increase the tractor’s driving range.
“Everywhere people are working on the hydrogen storage problem,” said Clement. “But I think the fact that we can work on both the use and the storage problem simultaneously is particularly valuable. And I think if storage is solved or even improved, hydrogen is going to be a very, very viable fuel for internal combustion engines.”
As for the tractor’s engine deficiency, the students think a larger regulator valve that permits higher pressure will solve the issue. They aren’t sure who will take on the tractor project next, but they’re proud of the work they’ve done, and they plan to use their newly acquired skills and knowledge in the future.
“These are young minds. These are some of the brightest students we have at Middlebury,” said Catlin. “They’ve absorbed all this in a short time, improved on it and think where they’re going with it in the future. That’s what excites us.”
At that point, the tractor had been running on low for quite some time. It wasn’t hooked up to an exhaust system like the other fossil-fuel equipment in the room, which would otherwise asphyxiate workers. There was no need. The tractor was quietly emitting water vapor into the room.
One of the mechanics turned on a nearby tractor to move it outside, and a dark plume of smoke poured out across the room.
Reporter Andrew Stein is at firstname.lastname@example.org.
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